Switch



Sept. 8, 1959 R. M. BLEAKNEY x-:TAL 2,903,534

SWITCH Original Filed July 9. 1942 2 Sheets-Sheet 1 FIG.4.

FIG.5.

INVENTORS .BLEAKNEY X BY Sept 8, 1959 R. M. LEAKNEY Erm? 2,903,534

SWITCH Original Filed July` 9, 1942 2 Sheets-Sheet 2 BH4/MSW 39 INVENTORS R. M. BLEAKNEY BY E.

United States Patent O SWII CH Robert M. Bleakney and Everly J. Workman, Albuquerque, N. Mex., assignors `to the United States of America as represented by the Secretary of the Navy Original application July 9, 1942, Serial No. 450,344,

now Patent No. 2,712,791, dated July 12, 1955. Divided and this application August 14, 1953, Serial No. 374,452

7 Claims. (Cl. 20G-61.08)

This invention relates generally to electrical shortcircuiting means, `and more particularly to an electrical switching mechanism of the type operated by the centrifugal force produced by rotation of a projectile when iired from a gun. This patent application is a division of co-pending U.S. patent application, Serial No. 450,344, tiled Iuly 9, 1942, by the same inventors, now Patent No. 2,712,791.

Certain types of projectiles are provided with electrical detonating devices by virtue of which the explosive charge is set off by electricity supplied by a battery provided Within the shell body.

One of the difficulties sometimes encountered in the operation of this type of detonating device is that the charge will be exploded too soon after the shell has started on its way, causing damage to the gun.

It is, therefore, an object of this invention to prevent premature detonating of the explosive charge in a projectile. v

It is also an object of this invention to prevent premature operation of an electrical detonating mechanism contained Within a projectile.

It is a further object of this invention that in the event an electrical impulse is transmitted to the squib by a fuze mechanism, this impulse will not operate the squib until some time after the projectile has been tired from its gun.

Further objects and many of the attendant advantages of this invention will become evident in the following detailed description taken in connection with the accompanying drawings in which:

Fig. l is a plan view of a `supporting element which ts within a projectile body embodying the invention;

Fig. 2 is a view in axial section, taken along line 2-2 of Fig. 1;

Fig. 3 is a sectional view of the time delay circuitbreaker which forms the principal element of the invention, taken along line 3 3 of Fig. 1;

Fig. 4 is a view similar to Fig. 3, except that centrifugal force has begun to operate on the mechanism;

Fig. 5 is an enlarged sectional view of the time-delay mechanism showing its operation completed by centrifugal force and the electrical circuit open;

Fig. 6 is a schematic wiring diagram of the electrical detonatin-g circuit;

Fig. 7 is similar to Fig. 6 except that the time-delay mechanism is shown in the open-circuit position;

Fig. 8 is a sectional view of a modified form of the time delay circuit-breaker showing its position within its supporting element;

Fig. 9 is a schematic Wiring diagram of the modied form of the electrical detonating circuit; and

Fig. 10 is an enlarged sectional view of the modified form of the time delay mechanism showing its operation completed by centrifugal force and the electrical circuit closed.

Referring now t-o the drawings, on which like numerals of reference are employed to designate like parts through- Miceout the several views, and more particularly to Figs. l and 2 thereof, there is shown therein a supporting element 11, which is substantially cylindrical in shape. The supporting element is provided with threads 12 which enable it to be screwed into a suitable place provided with matching threads within the casing of a projectile (not shown). The disposition of this member is such that the axis of rotation X-X of the supporting element will coincide with that of the projectile. Internal threads 13 are provided, into which the usual booster charge may be inserted. A communicating chamber 14 permits the booster charge to be red by the squib 15. The squib receives an electrical firing impulse, in a manner later to be described, at the appropriate time by means of the wires 16 and 17. As will be noted from Figs. l and 2, the squib 15 is held in place by a closure plug 18 provided with a thread which may be screwed into the tapped hole 19 provided in the supporting element 11.

An electrical time-delay switch mechanism 19 is placed within a cylindrical opening 21 provided in the supporting element 11. This switch mechanism is shown in detail in Figs. 3, 4, and 5. A cylindrically shaped outer insulating member 22 is supported within the opening 21. Within the insulating member 22 a metal tube 23 is tted. The outer insulating member may be cut away as at 22a to give accessibility for wiring. Annular shoulders 20 are provided on the interior surface of each end of the tube 23, and the discs 24 and 25 are litted into the ends of the tube against these shoulders and held in place by spinning over the rims of the tube. The disc 24 should be composed of an electrically conductive material and has a small centrally located hole provided therein, while its central inner surface may be recessed as at 24a. The disc 25 may be made of any suitable material as its purpose is to seal the end of the tube and to act as a support for one end of the spring 26.

The other end of the spring 26 presses against the bottom of an annular channel cut in one end of a plunger or piston 27 which slides with a loose iitv within the tube 23. The pressure of the spring tends to maintain the plunger in the position in which it is shown in Fig. 3. The plunger 27 is provided with an axial bore 28 which extends from an annular recess 29 at the outer end to a `smaller bore 31 at the inner end. The recess 29 is closed by means of a plug 32.

Fitted within the insulating member 22 and abutting the inner end of the metal tube 23 is a disc 33 of suitable insulating material and another disc 34 of electrically conductive material. These discs are also provided with centrally positioned openings or apertures in axial alignment with the hole provided in disc 24. An electrical connection is made between the discs 24 and 34 by means of the centrally disposed wire 35 which also extends through the small bore 31 of the plunger 27 into the axial bore 28. This wire is initially attached to the disc 34 by means of a drop of solder 36, and to the disc 24 by another drop of solder 37. An enlargement 38 is provided on the end of the wire 35 which lies within the axial bore 28. This enlargement may be made by knotting the end of the wire and applying a drop of solder, or may comprise any other suitable arrangement. The enlargement, however, should be of a size such that it will move freely within the axial bore 28 but Will not pullA through the smaller bore 31.

The electrical circuit is shown diagrammatically in Figs. 6 and 7. A battery 39, or other source of electric current is provided within the body of the projectile. A wire 41 leads from this battery 39 to the squib 15, while a return wire 42 from the squib leads to a circuitclosing means A, thence to the other side of the battery through the wire 43. The circuit-closing means A may comprise any device which operates by means of electrical radiations, sound waves, light rays, radiant heat, or by any other suitable means to result in the sending of an electrical impulse through the squib 15 when the projectile is in proximity to a target, or which may actuate the squib in response to a prearranged signal and, per se, forms no part of this invention. An electrical short-circuit across the squib 15 is initially obtained by means of the leads 44 and 45, which run from the wires 41 and 42, respectively, to the metal tube 23 and the conductive disc 34, respectively. Thus the initial electrical circuit, in the event the device A should permit a flow of electricity from the battery 39 would be from one side of the battery through lead 43 to the device A, to lead 42, thence through lead 45 to disc 34, wire 35 to disc 24, metal tube 23, lead 44, thence to the other side of the battery 39 through lead 41. The squib 15, being thus short-circuited, would receive no current and the projectile is rendered safe, regardless of the action of the device A.

The operation of the preferred form of the invention here disclosed, therefore, is to break this short-circuit when the projectile is red from a gun, and only then. In addition, the operation of the device contemplates a short time-lag before it is broken which will enable the n projectile to pass beyond the range of nearby objects before the squib 15 is rendered capable of being exploded by the electrical charge controlled by the device A.

The breaking of the short-circuit is controlled by the operation of the plunger 27. When the projectile is at rest, the spring 26 maintains the plunger in the position shown in Fig. 3, as before stated. However, as soon as the projectile is iired, the rilling of the gun causes it to rotate about the axis X--X. Inasmuch as the center of mass of the plunger 27 is to one side of the axis of rotation, it will be forced by centrifugal force against the pressure of spring 26, toward the outer end of the tube 23 until it reaches the position shown in Fig. 4. In addition to the pressure of the spring, another retarding influence is produced by light oil or other suitable fluid with which the interior of the tube is filled. The plunger is tted rather loosely within the tube so as to provide enough clearance to allow the passage of the oil as shown by the arrows 46.

A special advantage results from the presence of the oil. A momentarily heavy shock in handling a projectile might result in compressions of the spring 26 so as to permit the plunger 27 to open the circuit, whereas the pressure of the oil in the cylinder acts as a buier to limit movement of the plunger except when acted upon by a continuing force such as that produced by centrifugal force when a projectile is rotating at high speed.

The length of the wire 35 is such that when the plunger has reached the position shown in Fig. 4, the enlargement 38 will abut the shoulder formed by the junction between the bores 31 and 28. Further outward movement of the plunger will, therefore, result in the severance of the frangible connection between the wire 35 and the drops of solder 36 and 37 on the discs 34 and 24, respectively. When the plunger has reached the end of its travel, as shown in Fig. 5, the wire has been pulled entirely away from the disc 34 and the short-circuit is broken as shown by the electrical diagram in Fig. 7. It will be understood that the length of the wire 35 may be adjusted so that the movement of the plunger 27 will pull the wire entirely away from both discs but this is not essential to the breaking of the short-circuit. The short-circuit being broken, the squib 15 may Abe exploded, although it is obvious that it will not be actuated merely by the breaking of the short-circuit. The electrical tiring impulse must be supplied to the squib from the battery by virtue of some operation of the device A, which will be dependent upon the position of the shell with respect to a target, or upon the opera- 4 tion of some prearranged signal means to which it may respond.

In the modified form of the invention as shown in Figs. 8 through 10, the mechanical operation is substantially the same as that previously described in the preferred form of the invention, the main distinction between the two forms being in the electrical detonating circuit. In the modied form, the circuit extends directly from the battery 39 or other source of electrical current through wire 41 to the squib 15. The other side of the circuit extends from the battery 39 to the fuze A and hence to conductive disc 34 through Wire 43. AsV readily seen in Fig. 9, the circuit is normally broken between conductive disc 34 and a corresponding conductive disc 34a. Wire 42 completes the circuit from disc 34a tothe squib 15.

In Fig. 8, the time-delay switch mechanism is shown in its normal position, wherein the spring 26 retains the plunger 27 in its right-hand position. The connecting wire 35 with its enlargement 38 extends from the axial bore 28 in the plunger 27 through an aperture in the supporting disc 24, and is held in its position by solder 37. When the parts are in this position, the electrical circuit is broken between conductive discs 34 and 34a, and, hence, current cannot be supplied to the squib, thus rendering the projectile safef When the projectile has been tired from a riiled gun, a centrifugal force will act upon the plunger 27. The oil contained within the cylinder 23, aided by the action of the spring 26 will tend to overcome a portion of the centrifugal force, thus permitting the plunger 27 to move slowly to its position as shown in Fig. l0. As the plunger 27 nears the end of its displacement, the abutment 38 formed on wire 35 will rest against the end of the axial bore 28 formed in the plunger 27. Further displacement of the plunger 27 will move the wire 35 (breaking the solder 37) to the left, and through apertures formed in conductive discs 34 and 34a, thereby making contact between the conductive discs. Thus, the circuit is closed from the supply source 39 to the squib 15, except for the fuze A, and when the fuze A is actuated as previously described, the squib 15 will be detonated, which, in turn, tires the projectile.

While the invention has been described with reference to certain preferred examples thereof which give satisfactory results, it will be understood by those skilled in the art to which the invention pertains, after understanding the invention, that various changes and modications may be made without departing from the spirit and scope of the invention, and it is intended, therefore, to cover in the appended claims all such changes and modifications.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

l. A switching mechanism capable of being operated by centrifugal force, comprising in combination, a plurality of electrical contacts, a conducting element frangibly connected to said contacts, a relatively heavy mass operatively connected to said conducting element capable of being displaced by centrifugal force for severing the connection between said conducting element and at least one of said contacts.

2. A switching mechanism capable of being operated by centrifugal force, comprising in combination a plurality of electrical contacts, a conducting element frangibly connected to said contacts, a relatively heavy mass operatively connected to said conducting element capable of being displaced by centrifugal force so as to sever the connection between said conducting element and at least one of said contacts, and means to inhibit rapid movement of said relatively heavy mass.

3. A switching mechanism capable of being operated by centrifugal force, comprising in combination a plurality of electrical contacts, a conducting element frangibly connected to said contacts, a cylinder, a relatively heavy operatively connected to said conducting element and disposed within said cylinder so as to be capa` ble of being displaced by centrifugal force, thereby sever ing the connection between said conducting element and at least one of said contacts, said cylinder containing fluid for inhibiting rapid movement of said relatively heavy mass.

4. A switching mechanism capable of being operated by centrifugal force, comprising in combination a plurality of electrical contacts, a conducting element frangibly connected to said contacts, a cylinder, a plunger operatively connected to said conducting element loosely disposed within said cylinder so as to be capable of being displaced by centrifugal force thereby severing the connection between said conducting element and at least one of said contacts, said cylinder containing fluid for inhibiting rapid movement of said plunger.

5. A switching mechanism capable of being operated by centrifugal force comprising, in combination, a plurality of electrical contacts, a conducting element frangibly connected to said contacts, a cylinder, a plunger operatively connected to said conducting element and disposed within said cylinder so as to be capable of being displaced by centrifugal force for severing the connection between said conducting element and at least one of said contacts, said connection between said plunger and said conducting element permitting relative movement between said plunger and said conducting element so that said plunger does not actuate said conducting element at the beginning of the displacement of said plunger.

6. A switching mechanism capable of being operated by centrifugal force comprising in combination, a plurality of electrical contacts, a conducting element frangibly connected to said contacts, a cylinder, a plunger disposed within said cylinder and capable of being displaced by centrifugal force, means connecting said plunger with said conducting element so that displacement of said plunger will sever the connection between said conducting element and at least one of said contacts, said connecting means including a bore in said plunger through which said conducting element loosely extends for permitting relative movement between said plunger and said conducting element, and means on said conducting element for causing movement of said conducting element when said plunger nears the end of its displacement.

7. A switching mechanism capable of being operated by centrifugal force comprising, in combination, a plurality of electrical contacts, a conducting element frangibly connected to said contacts, a cylinder, a plunger disposed withn said cylinder and capable of being displaced by centrifugal force, means connecting said plunger with said connecting element so that displacement of said plunger will sever the connection between said conducting element and at least one of said contacts, said connecting means including a bore in said plunger through which said conducting element loosely extends for permitting relative movement between said plunger and said conducting element and means on said conducting element for causing movement of said conducting element when said plunger nears the end of its displacement, and means in said cylinder including uid for preventing rapid displacement of said plunger.

References Cited in the le of this patent UNITED STATES PATENTS 2,105,286 Jennings Ian. l1, 1938 FOREIGN PATENTS 381,635 Great Britain Oct. 13, 1932 376,987 Italy Dec. 4, 1939 

